A two-dimensional theoretical and numerical model of biomass pyrolysis has been developed to determine the kinetic of wood particles pyrolysis in a fixed bed reactor. The adopted chemical model is coupled with a global transport bi-dimensional, and two temperatures model. The three modes of heat transfer (conduction, convection and/or radiation) between the solid and gas phases, and the wall are considered. The system of all unsteady and reactive equations is resolved by a finite volume method with a hybrid spatial interpolation and an implicit interpolation for time. The resulting algebraic equations are then resolved by using the bi-conjugate gradient stabilized and normalized method. The obtained model is validated in several experimental cases for data of one biomass particle. This model is applied to predict the pyrolysis phenomenon in a fixed bed of particles. Using the proposed numerical model the time space evolutions, of temperature and char fraction, are presented and discussed. In this configuration, the obtained numerical results agree with the experimental data found in the literature.

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de ROUEN, Saint Etienne du Rouvray, Cedex, France AU Jemni A. AF Laboratoire d?Etudes de Syst?mes thermiques et Energ?tique (LESTE), Monastir, Tunisie KW premixed turbulent combustion % numerical simulation % V-flame KR nema AB In this paper we simulate a turbulent premixed V-shape flame stabilized on a hot wire. The device used is composed of a vertical combustion chamber where the methane-air mixture is convected upwards with a mean velocity of 4ms-1. The flow was simulated running Fluent 6.3, which numerically solved the stationary Favre-averaged mass balance; Navier-Stokes equations; combustion progress variable, and k-? equations on a two-dimensional numerical mesh. We model gaseous mixture, ignoring Soret and Dufour effects and radiation heat transfer. The progress variable balance equation was closed using Eddy Break Up model. The results of our simulations allow us to analyze the influence of equivalence ratio and the turbulent intensity on the properties of the flame (velocity, fluctuation, progress variable and Thickness of flame).This work gives us an idea on the part which turbulence can play to decrease the risks of extinction and instabilities caused by the lean premixed combustion. nema